Sentence examples for firstborn reduced from inspiring English sources
However, as expected, not being a firstborn reduced the risk of being SGA.
Instead, our findings are consistent with the maternal capital hypothesis (46), and they indicate that firstborns have reduced access to the maternal nutritional supply during pregnancy, resulting in their smaller size at birth.
The fact that, in contrast, survival was not significantly reduced for firstborn sons could be due to an increased effort made by parents to protect the life of their first son, especially in his early years, because at that time he is still the only son they have, and therefore the only potential heritor of their wealth.
That we did not find reduced fitness among firstborns suggests some degree of compensatory investment following birth either directly through (grand parents or through sibling competition.
The reduced birth size of firstborns therefore appears due to reduced access to maternal resources rather than the inadequacy of those resources.
We previously observed reduced activity levels in firstborns in this cohort at 11 years and suggested that the number of siblings might explain this association (30).
Women with older siblings had a reduced risk of breast cancer compared to those firstborn (OR = 0.3, 95% CI0.2 0.7).
These changes do not completely disappear following the pregnancy, such that subsequent offspring are from the start of pregnancy exposed to reduced vascular resistance and hence greater uterine blood flow compared with firstborns, promoting fetal growth (9).
Clearly, more data from cetaceans in general and from bottlenose dolphins in particular would not only reduce the prediction confidence intervals but would also provide greater power in distinguishing the effect of being a "firstborn" calf per se on survivorship.
